code: def test_function(self, x, y):
      # The best x is 2
      return (
          np.exp(-((x - 2) ** 2))
          + np.exp(-((x - 6) ** 2) / 10)
          + 1 / (x**2 + 1)
      )
  
file_path: advisor/advisor_server/suggestion/algorithm/bayesian_optimization.py
imports: from __future__ import print_function
  from __future__ import division
  import json
  import numpy
  from sklearn.gaussian_process import GaussianProcessRegressor
  from sklearn.gaussian_process.kernels import Matern
  from suggestion.models import Study
  from suggestion.models import Trial
  from suggestion.algorithm.abstract_algorithm import AbstractSuggestionAlgorithm
  from suggestion.algorithm.random_search import RandomSearchAlgorithm
label_desc: Use image node_id 2 for calling the BayesianOptimizationDemo obj's underlying member method code with example usage: obj.test_function(x, y) and returns: unknown